The present invention is an improvement over the edge mounted loading lip extender operating mechanisms disclosed in my U.S. Pat. Nos. 3,974,537 and 4,065,824. The operating mechanisms disclosed in each of my earlier granted patents are actuated by manually lifting the dock levelling plates from a position behind the dock levelling plates that have led to back injuries to the personnel lifting the dock levelers in the manner disclosed in my above U.S. patents. U.S. Pat. No. 4,065,824 aids the worker to lift the dock levelling plates by the provision of a counter-balance in the form of an elongated heavy duty coil spring for exerting pressure to assist the operating personnel in lifting the weight of the dock levelling plates consisting of a bridge plate pivotably mounted to the loading dock and a load levelling plate pivoted to the bridge plate to be movable therewith. The counter-balance spring mentioned also functions to resist the downward movement of the dock levelling plates in providing a counter-balancing force when the load levelling plate is moved downwardly for positioning it on the bed of a truck parked adjacent the loading/unloading dock.